Wound closure technology continues to evolve with non-suture alternatives such as staples, surgical tapes, and most recently, tissue adhesives, which have rapidly gained recognition and acceptance as effective wound closure methods. Two different forms of tissue adhesives for wound closure have been extensively studied: cyanoacrylate tissue adhesives and fibrin sealants. Fibrin sealants have not gained acceptance because of the low tensile strength of the fibrin polymer, lengthy preparation time, and the risk of viral transmission. The cyanoacrylates are recognized as superior adhesives for skin wound closure and are undergoing continuous modification to improve the technology.
A common property of all of the cyanoacrylates is the ability to bond and polymerize in the presence of water and to form a bond between the two sides of a wound to hold it in position. When used for wound closure, the cyanoacrylate polymerizes in the presence of water molecules on the skin surface, forming a bridge and bond that keeps the tissue together for the purpose of wound healing. The polymerized material then progressively and slowly flakes off after holding the skin tissues in that position. The difficulties and hazards associated with the use of cyanoacrylates are well known. Entry of cyanoacrylates into the wound promotes infection and a foreign body reaction. The cyanoacrylates are toxic and there may be adverse reactions because of hypersensitivity to cyanoacrylates themselves or formaldehyde, one of the starting materials used for preparing cyanoacrylate adhesives.
The first cyanoacrylates used as tissue adhesives included the short chain cyanoacrylates, commonly referred to as Super Glues™, were associated with severe acute and chronic inflammatory reactions. Subsequently, longer chain cyanoacrylates, including butyl and octyl cyanoacrylates have gained acceptance. While butyl cyanoacrylates provide effective closure of simple superficial lacerations and incisions, they are toxic when introduced into vascular areas and exhibit low tensile strength and high brittleness.
Octyl cyanoacrylates have proved to be superior adhesives for wound closure, demonstrating greater tensile strength than the butyl cyanoacrylates, and are remarkably nontoxic when used for skin wound closure, but may be toxic if allowed to enter the wound. Octyl cyanoacrylate has been approved by the FDA for use as a tissue adhesive. However, there are problems associated with its use, including a higher incidence of wound infection when compared to suturing as a wound closure method. Also, blood and body fluids trigger premature polymerization of the cyanoacrylate, resulting in an unsightly plasticized mass with very little skin bonding. It is also difficult to keep adhesive out of the wound. The polymerization reaction is exothermic, and the generated heat can result in patient discomfort. Octyl cyanoacrylates may have a low viscosity, causing them to run into undesirable areas or into the wound. For example, cyanoacrylates running into the eye can result in tarsorrhaphy (lid fusion) or corneal injury.